Differentials of the type to which the present invention relates are commonly used in vehicles to transmit torque from a drive shaft to a pair of driven shafts. In many of these differentials, a C-washer axle shaft retention system is used to hold the driven shafts in the differential case, and it is common to provide a slip fit between the pinion shaft (also referred to as the cross shaft) and the differential case. While this construction allows for ease of assembly and disassembly, it also can lead to unexpectedly high wear of the case, particularly in a critical area where the ends of the pinion shaft are received and held in the case. It is therefore an advantage of the present invention to reinforce this critical wear area in the differential case, and, additionally, to provide the capability of replacing the area subject to the greatest amount of wear without requiring replacement of the entire differential case.